Porous materials for solid phase extraction and chromatography and processes for preparation and use thereof

ABSTRACT

Embodiments of the present invention are directed to porous materials for use in solid phase extractions and chromatography. The materials feature at least one hydrophobic component, at least one hydrophilic component and at least one ion-exchange functional group. The materials exhibit superior wetting and ion-exchange performance.

REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 10/782,397, filed Feb. 18, 2004, now U.S. Pat. No. 7,731,844,which is a continuation-in-part of U.S. application Ser. No. 10/169,546now U.S. Pat. No. 7,232,520, which entered the U.S. national stage onJan. 16, 2003, as the U.S. national phase application of PCTinternational application No. PCT/US99/13241, filed on Jun. 10, 1999,which claims the benefit of U.S. provisional application Ser. No.60/089,153, filed on Jun. 12, 1998. The present application alsocontains subject matter that is related to that disclosed and claimed inU.S. application Ser. No. 09/505,456, filed on Feb. 11, 2000, now U.S.Pat. No. 6,322,695, which is a continuation-in-part of PCT internationalapplication No. PCT/US99/13241, filed on Jun. 10, 1999, which claimspriority to U.S. provisional application Ser. No. 60/089,153, filed onJun. 12, 1998. The disclosures of all the aforementioned patentapplications and the aforementioned patent are incorporated herein intheir entireties by this reference.

BACKGROUND OF THE INVENTION

Solid phase extraction (SPE) is a chromatographic technique that iswidely used, e.g., for preconcentration and cleanup of analyticalsamples, for purification of various chemicals, and for removal of toxicor valuable substances from aqueous solutions. SPE is usually performedusing a column or cartridge containing an appropriate material orsorbent. SPE procedures have been developed using sorbents that caninteract with analytes by hydrophobic, ion-exchange, chelation,sorption, and other mechanisms, to bind and remove the analytes fromfluids.

Because different SPE applications can require different sorbents, thereis a need for sorbents with novel properties that have uniqueselectivities. These include superior wetting characteristics, selectivecapture of analytes of interest, and non-retention of interferinganalytes. Sorbents comprising porous particles having the aforementionedproperties are described in WO 99/64480 and in U.S. Pat. No.6,322,695B1.

However, a problem associated with porous particles is the passage orleaching of particles through the retaining frit of the separationdevice into the sample of interest. In addition to contamination of thesample, the passed particles can further negatively impact test methodsand the HPLC systems that are used to test the samples. For example, theparticles may clog or block in line filters or column frits which inturn lead to high system backpressures and ultimately HPLC pumpshutdown.

Monolith materials have been developed in an attempt to overcome theproblem of particle passage or leaching through frits. These includepolymeric monoliths such as polymethacrylate monoliths (U.S. Pat. No.5,453,185, U.S. Pat. No. 5,728,457); polystyrene—DVB monoliths (U.S.Pat. No. 4,889,632, U.S. Pat. No. 4,923,610, U.S. Pat. No. 4,952,349);charge incorporated polymethacrylate monoliths for the application ofreversed-phase ion-pairing chromatography (U.S. Pat. No. 6,238,565);monoliths based on ROMP metathesis (WO 00073782); and (EP 852334)continuous monolith columns made from water-soluble polymerizablemonomers, such as vinyl, allyl, acrylic and methacrylic compounds,without porogens but in the presence of high concentration of inorganicsalts such as ammonium sulfate.

Polymeric monoliths are chemically stable against strongly alkaline andstrongly acidic mobile phases, allowing flexibility in the choice ofmobile phase pH. However, the prior art monoliths do not necessarilyprovide the unique selectivities and advantages that are needed for avariety of chromatographic applications, in particular SPE applications.

SUMMARY OF THE INVENTION

The invention is directed to novel porous materials that are useful inchromatographic processes, e.g., solid phase extraction, and thatprovide a number of advantages. Such advantages include superior wettingcharacteristics, selective capture of analytes of interest, andnon-retention of interfering analytes. The invention also provides novelporous materials that overcome the problems of particle passage throughfrits.

Thus, in a first aspect, the invention provides a porous materialcomprising a copolymer of at least one hydrophobic monomer and at leastone hydrophilic monomer, wherein said copolymer further comprises atleast one ion-exchange functional moiety selected from the groupconsisting of an acyclic secondary amine exclusive of polyethylenimine,a cyclic tertiary amine, a substituted acyclic amine, and a substitutedcyclic amine.

In a second aspect, the invention provides a copolymer having theformula I:-(-A-)_(n)-(—B—)_(m)-(—C—)_(p)—  (I)and salts thereof,

wherein the order of repeat units A, B and C may be random, block, or acombination of random and block;

wherein

$\frac{1}{100} < \frac{\left( {p + n} \right)}{m} < \frac{100}{1}$ and$\frac{1}{500} < \frac{p}{n} < \frac{100}{1}$

wherein A is selected from the group consisting of

wherein B is selected from the group consisting of

wherein C is modified A, wherein modified A is selected from the groupconsisting of

and

wherein X is —CR₁R₂NR₃R₄ wherein:

R₁ and R₂ are the same or different and each is hydrogen or C₁-C₆ alkyl;

R₃ and R₄ are the same or different and each is hydrogen, an electronwithdrawing group, C₁-C₂₀ alkyl, C₁-C₂₀ alkyl substituted by an electronwithdrawing group, or R₃ and R₄ taken together form a carbocyclic ringor a heterocyclic ring, wherein the carbocyclic ring or heterocyclicring can be substituted by an electron withdrawing group, provided that(i) R₁, R₂, R₃, and R₄ are not all hydrogen; (ii) if R₁ and R₂ arehydrogen, then R₃ and R₄ are not both unsubstituted C₁-C₂₀ alkyl; and(iii) if R₁ and R₂ are hydrogen, and either of R₃ and R₄ is hydrogen,then the other of R₃ and R₄ is not polyethylenimine.

In accordance with the invention, the porous materials disclosed hereincan take the form of porous particles or monoliths. Thus, in yet anotheraspect, the invention provides a porous material comprising a porousparticle that comprises a copolymer described above with regard to thefirst and second aspects of the invention. Likewise, the inventionprovides a porous material comprising a porous monolith that comprises acopolymer described above with regard to the first and second aspects ofthe invention.

In another aspect, the invention also provides solid phase extractionand chromatography materials comprising porous materials of theinvention.

In yet another aspect, the invention provides a separation devicecomprising a porous material of the invention. In a related aspect, theinvention provides a solid phase extraction cartridge comprising aporous materials according to the invention.

The invention also provides a method for removing or isolating acomponent from a mixture. The method comprises contacting the mixturewith a chromatographic material comprising the porous material accordingto the invention, to thereby remove or isolate the component from themixture.

In another aspect, the invention provides a method for determining thelevel of a component in a mixture. The method comprises contacting themixture with a chromatographic material comprising a porous materialaccording to the invention under conditions that allow for sorption ofthe component onto the porous material; washing the chromatographicmaterial having the sorbed component with a solvent under conditions soas to desorb the component from the porous materials; and determiningthe level of the desorbed component.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts the total ion chromatogram (TIC) obtained using theproduct of Example 3b.

FIG. 2 depicts the total ion chromatogram (TIC) obtained using theproduct of Example 3f.

DETAILED DESCRIPTION OF THE INVENTION Definitions

The present invention will be more fully illustrated by reference to thedefinitions set forth below.

The term “alicyclic group” includes closed ring structures of three ormore carbon atoms. Alicyclic groups include cycloparaffins or naphthenesthat are saturated cyclic hydrocarbons, cycloolefins that areunsaturated with two or more double bonds, and cycloacetylenes, whichhave a triple bond. They do not include aromatic groups. Examples ofcycloparaffins include cyclopropane, cyclohexane, and cyclopentane.Examples of cycloolefins include cyclopentadiene and cyclooctatetraene.Alicyclic groups also include fused ring structures and substitutedalicyclic groups such as alkyl substituted alicyclic groups. In theinstance of the alicyclics such substituents may further comprise alower alkyl, a lower alkenyl, a lower alkoxy, a lower alkylthio, a loweralkylamino, a lower alkylcarboxyl, a nitro, a hydroxyl, —CF₃, —CN, orthe like.

The term “aliphatic group” includes organic compounds characterized bystraight or branched chains, typically having between 1 and 22 carbonatoms. Aliphatic groups include alkyl groups, alkenyl groups and alkynylgroups. In complex structures, the chains may be branched orcross-linked. Alkyl groups include saturated hydrocarbons having one ormore carbon atoms, including straight-chain alkyl groups andbranched-chain alkyl groups. Such hydrocarbon moieties may besubstituted on one or more carbons with, for example, a halogen, ahydroxyl, a thiol, an amino, an alkoxy, an alkylcarboxy, an alkylthio,or a nitro group. Unless the number of carbons is otherwise specified,“lower aliphatic” as used herein means an aliphatic group, as definedabove (e.g., lower alkyl, lower alkenyl, lower alkynyl), but having fromone to six carbon atoms. Representative of such lower aliphatic groups,e.g., lower alkyl groups, are methyl, ethyl, n-propyl, isopropyl,2-chloropropyl, n-butyl, sec-butyl, 2-aminobutyl, isobutyl, tert-butyl,3-thiopentyl, and the like. As used herein, the term “nitro” means —NO₂;the term “halogen” designates —F, —Cl, —Br or —I; the term “thiol” meansSH; and the term “hydroxyl” means —OH.

The terms “alkenyl” and “alkynyl” refer to unsaturated aliphatic groupsanalogous to alkyls, but which contain at least one double or triplebond respectively. Suitable alkenyl and alkynyl groups include groupshaving 2 to about 12 carbon atoms, preferably from 1 to about 6 carbonatoms.

The term “alkoxy” as used herein means an alkyl group, as defined above,having an oxygen atom attached thereto. Representative alkoxy groupsinclude groups having 1 to about 12 carbon atoms, preferably 1 to about6 carbon atoms, e.g., methoxy, ethoxy, propoxy, tert-butoxy and thelike.

The term “alkyl” includes saturated aliphatic groups, includingstraight-chain alkyl groups, branched-chain alkyl groups, cycloalkyl(alicyclic) groups, alkyl substituted cycloalkyl groups, and cycloalkylsubstituted alkyl groups. In certain embodiments, a straight chain orbranched chain alkyl has 30 or fewer carbon atoms in its backbone, e.g.,C₁-C₃₀ for straight chain or C₃-C₃₀ for branched chain. In certainembodiments, a straight chain or branched chain alkyl has 20 or fewercarbon atoms in its backbone, e.g., C₁-C₂₀ for straight chain or C₃-C₂₀for branched chain, and more preferably 18 or fewer. Likewise, preferredcycloalkyls have from 4-10 carbon atoms in their ring structure, andmore preferably have 4-7 carbon atoms in the ring structure. The term“lower alkyl” refers to alkyl groups having from 1 to 6 carbons in thechain, and to cycloalkyls having from 3 to 6 carbons in the ringstructure.

Moreover, the term “alkyl” (including “lower alkyl”) as used throughoutthe specification and claims includes both “unsubstituted alkyls” and“substituted alkyls,” the latter of which refers to alkyl moietieshaving substituents replacing a hydrogen on one or more carbons of thehydrocarbon backbone. Such substituents may include, for example,halogen, hydroxyl, alkylcarbonyloxy, arylcarbonyloxy, alkoxycarbonyloxy,aryloxycarbonyloxy, alkylcarbonyl, alkoxycarbonyl, aminocarbonyl,alkylthiocarbonyl, alkoxyl, cyano, alkyl amino, arylamino, diarylamino,and alkylarylamino, acylamino (including alkylcarbonylamino,arylcarbonylamino, carbamoyl and ureido), amidino, imino, sulfhydryl,alkylthio, arylthio, thiocarboxylate, sulfamoyl, sulfonamido, nitro,trifluoromethyl, cyano, azido, heterocycyl, aralkyl, or an aromatic orheteroaromatic moiety. It will be understood by those skilled in the artthat the moieties substituted on the hydrocarbon chain may themselves besubstituted, if appropriate.

Cycloalkyls may be further substituted, e.g., with the substituentsdescribed above. An “aralkyl” moiety is an alkyl substituted with anaryl, e.g., having 1 to 3 separate or fused rings and from 6 to about 18carbon ring atoms, e.g., phenylmethyl (benzyl).

The term “alkylamino” as used herein means an alkyl group, as definedabove, having an amino group attached thereto. Suitable alkylaminogroups include groups having 1 to about 12 carbon atoms, preferably from1 to about 6 carbon atoms. The term “amino,” as used herein, refers toan unsubstituted or substituted moiety of the formula —NR_(a)R_(b), inwhich R_(a) and R_(b) are each independently hydrogen, alkyl, aryl, orheterocyclyl, but R_(a) and R_(b) are both not alkyl, or R_(a) andR_(b), taken together with the nitrogen atom to which they are attached,form a cyclic moiety having from 3 to 8 atoms in the ring. An“amino-substituted amino group” refers to an amino group in which atleast one of R_(a) and R_(b), is further substituted with an aminogroup.

Thus, the terms “alkylamino” and “amino” include acyclic primary aminessuch methylamine, ethylamine, propylamine, isopropylamine, butylamine,sec-butylamine, iso-butylamine, tert-butylamine, pentylamine,1,1-dimethylpropylamine, 1,2-dimethylpropylamine, 1-ethylpropylamine,2-methylbutylamine, isopentylamine, hexylamine, 1,3-dimethylbutylamine,3,3-dimethylamine, heptylamine, 2-aminoheptane, octylamine,1,5-dimethylhexylamine, 2-ethylhexylamine, 1-methylheptylamine,tert-octylamine, nonylamine, decylamine, undecylamine, dodecylamine,tridecylamine, tetradecylamine, pentadecylamine, hexadecylamine,heptadecylamine, octadecylamine, nonadecylamine, and eicosylamine.Preferred primary amines include propylamine, isopropylamine,butylamine, sec-butylamine, iso-butylamine, pentylamine, isopentylamine,hexylamine, heptylamine, 2-aminoheptane, octylamine, 2-ethylhexylamine,dodecylamine, or octadecylamine.

The terms “alkylamino” and “amino” also include cyclic secondary aminessuch as azirane, azetane, azolane, azinane, azepane, azocane, azonane,azecane, diazatene, diazolane, diazinane, N-methyldiazinane, diazepane,diazocane, diazonane, diazecane, and imidazole. Preferred cyclicsecondary amines include azinane, diazinane and N-methyl-diazinane.

The term “alkylthio” refers to an alkyl group, as defined above, havinga sulfhydryl group attached thereto. Suitable alkylthio groups includegroups having 1 to about 12 carbon atoms, preferably from 1 to about 6carbon atoms. The term “alkylcarboxyl” as used herein means an alkylgroup, as defined above, having a carboxyl group attached thereto.

The term “aromatic group” includes unsaturated cyclic hydrocarbonscontaining one or more rings. Aromatic groups include 5- and 6-memberedsingle-ring groups which may include from zero to four heteroatoms, forexample, benzene, pyrrole, furan, thiophene, imidazole, oxazole,thiazole, triazole, pyrazole, pyridine, pyrazine, pyridazine andpyrimidine, and the like. The aromatic ring may be substituted at one ormore ring positions with, for example, a halogen, a lower alkyl, a loweralkenyl, a lower alkoxy, a lower alkylthio, a lower alkylamino, a loweralkylcarboxyl, a nitro, a hydroxyl, —CF₃, —CN, or the like.

The term “aryl” includes 5- and 6-membered single-ring aromatic groupsthat may include from zero to four heteroatoms, for example,unsubstituted or substituted benzene, pyrrole, furan, thiophene,imidazole, oxazole, thiazole, triazole, pyrazole, pyridine, pyrazine,pyridazine and pyrimidine, and the like. Aryl groups also includepolycyclic fused aromatic groups such as naphthyl, quinolyl, indolyl,and the like. The aromatic ring may be substituted at one or more ringpositions with such substituents, e.g., as described above for alkylgroups. Suitable aryl groups include unsubstituted and substitutedphenyl groups. The term “aryloxy” as used herein means an aryl group, asdefined above, having an oxygen atom attached thereto. The term“aralkoxy” as used herein means an aralkyl group, as defined above,having an oxygen atom attached thereto. Suitable aralkoxy groups have 1to 3 separate or fused rings and from 6 to about 18 carbon ring atoms,e.g., O-benzyl.

The term “block ordering” is intended to include ordering in whichindividual units are joined in a pattern or repeated sequence.

The term “conjugate acid of an amine” describes a protonated amine thatis positively charged.

The term “copolymer” is intended to include a polymer comprising two ormore different monomers.

The term “electron withdrawing group” describes a substituent or groupthat has the effect of lowering the average pK_(a) of the conjugate acidof an amine substituted with the electron withdrawing group as comparedto the conjugate acid of that amine without the electron withdrawinggroup. Electron withdrawing groups in accordance with the inventioninclude halogens, aromatic groups, unsaturated groups, ethers,thioethers, nitriles, nitro groups, esters, amides, carbamates, ureas,carbonates, sulfonamides, sulfones, and sulfoxides. In addition, theterm is intended to include heteroatoms that substitute for ring carbonatoms in a heterocycle. Preferred electron withdrawing groups includehalogens, ethers, or an aromatic group.

The term “haloalkyl” is intended to include alkyl groups as definedabove that are mono-, di- or polysubstituted by halogen, e.g.,chloromethyl, fluoromethyl, bromomethyl, iodomethyl, andtrifluoromethyl.

The term “heteroatom” as used herein means an atom of any element otherthan carbon or hydrogen. Preferred heteroatoms are nitrogen, oxygen,sulfur and phosphorus.

The term “heterocyclic group” includes closed ring structures in whichone or more of the atoms in the ring is an element other than carbon,for example, nitrogen, sulfur, or oxygen. Heterocyclic groups may besaturated or unsaturated and heterocyclic groups such as pyrrole andfuran may have aromatic character. They include fused ring structuressuch as quinoline and isoquinoline. Other examples of heterocyclicgroups include pyridine and purine. Heterocyclic groups may also besubstituted at one or more constituent atoms with, for example, ahalogen, a lower alkyl, a lower alkenyl, a lower alkoxy, a loweralkylthio, a lower alkylamino, a lower alkylcarboxyl, a nitro, ahydroxyl, —CF₃, —CN, or the like. Suitable heteroaromatic andheteroalicyclic groups generally will have 1 to 3 separate or fusedrings with 3 to about 8 members per ring and one or more N, O or Satoms, e.g., coumarinyl, quinolinyl, pyridyl, pyrazinyl, pyrimidyl,furyl, pyrrolyl, thienyl, thiazolyl, oxazolyl, imidazolyl, indolyl,benzofuranyl, benzothiazolyl, tetrahydrofuranyl, tetrahydropyranyl,piperidinyl, morpholino and pyrrolidinyl.

Thus, the term “heterocyclic group” includes moieties such as azirane,azetane, azolane, azinane, azepane, azocane, azonane, and azecane thatare heterocyclic molecules containing a single nitrogen within a 3-, 4-,5-, 6-, 7-, 8-, 9-, and 10-membered ring respectively. These moleculesmay also have additional fused rings of the same or a differentstructure and may also have unsaturation. These molecules may be furthersubstituted with a variety groups including aliphatic groups, alicyclicgroups, heterocyclic groups, aromatic groups, and the like.

The term “heterocyclic group” also includes moieties such as diazatene,diazolane, diazinane, diazepane, diazocane, diazonane, and diazecanethat are heterocyclic molecules containing two nitrogens within a 4-,5-, 6-, 7-, 8-, 9- and 10-membered ring respectively. These moleculesmay also have additional fused rings of the same or a differentstructure and may also have unsaturation. These molecules may be furthersubstituted with a variety groups including aliphatic groups, alicyclicgroups, heterocyclic groups, aromatic groups, and the like.N-methylpiperazine is an example of a substituted diazinane. Imidazoleis an example of an unsaturated diazolane.

The term “heterocyclic group” further includes moieties such asoxazetane, oxazolane, oxazinane, oxazepane, oxazocane, oxazonane, andoxazecane” that are heterocyclic molecules containing one oxygen and onenitrogen within a 4-, 5-, 6-, 7-, 8-, 9-, and 10-membered ringrespectively. These molecules may also have additional fused rings ofthe same or a different structure and may also have unsaturation. Thesemolecules may be further substituted with a variety groups includingaliphatic groups, alicyclic groups, heterocyclic groups, aromaticgroups, and the like. Morpholine is an example of an oxazinane.

The term “heterocyclic group” also includes moieties such as thiazetane,thiazolane, thiazinane, thiazepane, thiazocane, thiazonane, andthiazecane that are heterocyclic molecules containing one sulfur and onenitrogen within a 4-, 5-6-, 7-, 8-, 9, and 10-membered ringrespectively. These molecules may also have additional fused rings ofthe same or a different structure and may also have unsaturation. Thesemolecules may be further substituted with a variety groups includingaliphatic groups, alicyclic groups, heterocyclic groups, aromaticgroups, and the like.

The term “hydrophilic” describes having an affinity for, attracting,adsorbing or absorbing water.

The term “hydrophobic” describes lacking an affinity for, repelling, orfailing to adsorb or absorb water.

The term “ion-exchange functional group” is intended to include a groupwhere the counter-ion is partially free and can readily be exchanged forother ions of the same sign.

The term “mole percent” describes the mole fraction, expressed as apercent, of the monomer of interest relative to the total moles of thevarious (two or more) monomers which compose the copolymer of the porousmaterial of the invention.

The term “monolith” is intended to include a porous, three-dimensionalmaterial having a continuous interconnected pore structure in a singlepiece. A monolith is prepared, for example, by casting precursors into amold of a desired shape. The term monolith is meant to be distinguishedfrom a collection of individual particles packed into a bed formation,in which the end product still comprises individual particles in bedformation.

The term “monomer” is intended to include a molecule comprising one ormore polymerizable functional groups prior to polymerization, or arepeating unit of a polymer.

The term “porous material” is intended to include a member of a class ofporous crosslinked polymers penetrated by pores through which solutionscan diffuse. Pores are regions between densely packed polymer chains.

The term “random ordering” is intended to include ordering in whichindividual units are joined randomly.

The term “solid phase extraction” is intended to include a processemploying a solid phase for isolating classes of molecular species fromfluid phases such as gases and liquids by, e.g., sorption, ion-exchange,chelation, size exclusion (molecular filtration), affinity or ionpairing mechanisms.

The term “sorption” describes the ability of a material to take up andhold another material by absorption or adsorption.

Compositions and Methods of the Invention

The invention provides a porous material comprising a copolymer of aleast one hydrophobic monomer and at least one hydrophilic monomer,wherein said copolymer further comprises at least one ion-exchangefunctional moiety selected from the group consisting of an acyclicsecondary amine exclusive of polyethylenimine, a cyclic tertiary amine,a substituted acyclic amine, and a substituted cyclic amine. Preferably,the porous material has a specific surface area in the range from about50 to about 850 square meters per gram and pores having a diameterranging from about 0.5 nm to about 100 nm. In certain embodiments, theporous material is incorporated in a matrix.

In certain embodiments, the porous materials of the invention take theform of porous particles, e.g., beads, pellets, or any other formdesirable for use. The porous particles can have, e.g., a sphericalshape, a regular shape or an irregular shape. Preferably, the particlesare beads having a diameter in the range from about 3 to about 500 μm,preferably from about 20 to about 200 μm.

In other embodiments, the porous materials of the invention take theform of porous monoliths. In certain embodiments, the monoliths have thefollowing characteristics: surface area ranging from about 50 to about800 m²/g, more particularly about 300 to about 700 m²/g; pore volumeranging from about 0.2 to about 2.5 cm³/g, more particularly about 0.4to about 2.0 cm³/g, still more particularly about 0.6 to about 1.4cm³/g; and pore diameter ranging from about 20 to about 500 Å, moreparticularly about 50 to 300 Å, still more particularly about 80 toabout 150 Å.

The porous materials of the invention comprise a copolymer comprising aleast one hydrophobic monomer and at least one hydrophilic monomer. Incertain embodiments, the copolymer of the invention is non-sulfonated.

In certain embodiments the hydrophobic monomer comprises an aromaticcarbocyclic group, e.g., a phenyl group or a phenylene group, or astraight chain C₂-C₁₈-alkyl group or a branched chain C₂-C₁₈-alkylgroup. The hydrophobic monomer can be, e.g., styrene or divinylbenzene.A preferred copolymer is a poly(divinylbenzene-co-N-vinylpyrrolidone).

In certain embodiments, the hydrophilic monomer comprises a heterocyclicgroup, e.g., a saturated, unsaturated or aromatic heterocyclic group.Examples include nitrogen-containing heterocyclic groups, e.g., apyridyl group, e.g., 2-vinylpyridine, 3-vinylpyridine or4-vinylpyridine, or a pyrrolidonyl group, e.g., N-vinylpyrrolidone.

In one embodiment, the hydrophobic monomer is divinylbenzene or styrene,and the hydrophilic monomer is N-vinylpyrrolidone or N-vinyl acetamide.In a specific embodiment, the copolymer is apoly(divinylbenzene-co-N-vinylpyrrolidone). Preferably, the porousmaterial comprises at least about 12 mole percent N-vinylpyrrolidone.More preferably, the porous material comprises at least about 30 molepercent N-vinylpyrrolidone.

The invention also provides porous materials wherein the hydrophobicmonomer is substituted by at least one haloalkyl group, and theion-exchange functional moiety is formed by reaction of the haloalkylgroup with an appropriate starting amine to form an amine selected fromthe group consisting of an acyclic secondary amine, a cyclic tertiaryamine, a substituted acyclic amine, and a substituted cyclic amine. Incertain embodiments, the haolalkyl group is fluoromethyl, choromethyl,bromomethyl or iodomethyl. In one embodiment, the haloalkyl group ischloromethyl.

Examples of primary amines that can be used in accordance with theinvention include methylamine, ethylamine, propylamine, isopropylamine,butylamine, sec-butylamine, iso-butylamine, tert-butylamine,pentylamine, 1,1-dimethylpropylamine, 1,2-dimethylpropylamine,1-ethylpropylamine, 2-methylbutylamine, isopentylamine, hexylamine,1,3-dimethylbutylamine, 3,3-dimethylamine, heptylamine, 2-aminoheptane,octylamine, 1,5-dimethylhexylamine, 2-ethylhexylamine,1-methylheptylamine, tert-octylamine, nonylamine, decylamine,undecylamine, dodecylamine, tridecylamine, tetradecylamine,pentadecylamine, hexadecylamine, heptadecylamine, octadecylamine,nonadecylamine, and eicosylamine. In certain embodiments, the primaryamine is propylamine, isopropylamine, butylamine, sec-butylamine,iso-butylamine, pentylamine, isopentylamine, hexylamine, heptylamine,2-aminoheptane, octylamine, 2-ethylhexylamine, dodecylamine, oroctadecylamine.

Examples of cyclic secondary amines in accordance with the inventioninclude azirane, azetane, azolane, azinane, azepane, azocane, azonane,azecane, diazatene, diazolane, diazinane, diazepane, diazocane,diazonane, diazecane, imidazole, oxazetane, oxazolane, oxazinane,oxazepane, oxazocane, oxazonane, oxazecane, thiazetane, thiazolane,thiazinane, thiazepane, thiazocane, thiazonane, and thiazecane. In oneembodiment, the cyclic secondary amine is 1,4-oxazinane. In anotherembodiment, the cyclic secondary amine is azinane. In yet anotherembodiment, the cyclic secondary amine is diazinane.

In accordance with the invention, the ion-exchange functional moiety canbe formed from a substituted acyclic amine or a substituted cyclicamine. The substitution can be at any of the ring atoms, includingheteroatoms. For example, in certain embodiments, the ion-exchangefunctional moiety is a substituted cyclic secondary amine, e.g.,N-methyldiazinane and 4-methylpiperidine.

In other embodiments, the aforesaid amines are advantageouslysubstituted by an electron withdrawing group. In certain embodiments,the electron withdrawing group is selected from the group consisting ofhalogens, aromatic groups, unsaturated groups, ethers, thioethers,nitriles, nitro groups, esters, amides, carbamates, ureas, carbonates,sulfonamides, sulfones, sulfoxides and heteroatoms, e.g., N, O and S. Incertain embodiments, the electron withdrawing group is a halogen, anether, or an aromatic group.

In accordance with the invention, the electron withdrawing group of theamine has the effect of lowering the average pK_(a) of the conjugateacid of the amine as compared to the conjugate acid of the amine withoutthe electron withdrawing group. In certain embodiments, the pK_(a)ranges from about 5 to about 7.

In certain embodiments, the acyclic amine substituted with an electronwithdrawing group includes benzylamine, N-methylbenzylamine,N-ethylbenzylamine, N-propylbenzylamine, N-butylbenzylamine,N-pentylbenzylamine, N-hexylbenzylamine, N-heptylbenzylamine,N-octylbenzylamine, N-nonylbenzylamine, N-decylbenzylamine,N-undecylbenzylamine, N-dodecylbenzylamine, N-tridecylbenzylamine,N-tetradecylbenzylamine, N-pentadecylbenzylamine,N-hexadecylbenzylamine, N-heptadecylbenzylamine, N-octadecylbenzylamine,dibenzylamine, aniline, N-methylaniline, N-ethylaniline,N-propylaniline, N-butylaniline, N-pentylaniline, N-hexylaniline,N-heptylaniline, N-octylaniline, N-nonylaniline, N-decylaniline,N-undecylaniline, N-dodecylaniline, N-tridecylaniline,N-tetradecylaniline, N-pentadecylaniline, N-hexadecylaniline,N-heptadecylaniline, N-octadecylaniline,bis(2,2,2-trifluoromethyl)amine, phenethylamine, N-methylphenethylamine,4-methylphenethylamine, 3-phenylpropylamine,1-methyl-3-phenylpropylamine, N-isopropylbenzylamine, and4-phenylbutylamine. In certain preferred embodiments, the acyclic aminesubstituted with an electron withdrawing group is benzylamine,N-methylbenzylamine, or phenethylamine. In a preferred embodiment, theacyclic amine substituted with an electron withdrawing group isN-methylbenzylamine.

In other embodiments, cyclic secondary amines substituted with anelectron withdrawing group include oxazetane, oxazolane, oxazinane,oxazepane, oxazocane, oxazonane, oxazecane, thiazetane, thiazolane,thiazinane, thiazepane, thiazocane, thiazonane, and thiazecane. In oneembodiment, the cyclic secondary amine is 1,4-oxazinane. In theseembodiments, one of ordinary skill in the art will appreciate that theelectron withdrawing group is a second heteroatom that has substitutedfor a carbon atom in the ring. For example, the ring carbon adjacent tothe nitrogen atom in azetidine is substituted by an oxygen to yieldoxazetane, an amine encompassed by the term “cyclic secondary aminesubstituted with an electron withdrawing group”.

The porous materials, in either porous particle or monolith form, areadvantageously used for solid phase extraction or chromatography. In aone embodiment, the porous material comprises at least one porousparticle, and more preferably a plurality of porous particles. In oneembodiment, the porous material comprises the copolymerpoly(divinylbenzene-co-N-vinylpyrrolidone). In a related embodiment, thepoly(divinylbenzene-co-N-vinylpyrrolidone) has ion-exchange functionalmoieties present at a concentration of about 0.01 to about 1.0milliequivalents per gram of porous material.

In another aspect, porous materials of the invention, in either porousparticle or monolith form, comprise novel copolymers. These copolymershave the formula I:-(-A-)_(n)-(—B—)_(m)-(—C—)_(p)—  (I)

and salts thereof,

wherein the order of repeat units A, B and C may be random, block, or acombination of random and block;

wherein

$\frac{1}{100} < \frac{\left( {p + n} \right)}{m} < \frac{100}{1}$ and$\frac{1}{500} < \frac{p}{n} < \frac{100}{1}$

wherein A is selected from the group consisting of

wherein B is selected from the group consisting of

wherein C is modified A, wherein modified A is selected from the groupconsisting of

and

wherein X is —CR₁R₂NR₃R₄ wherein:

R₁ and R₂ are the same or different and each is hydrogen or C₁-C₆ alkyl;

R₃ and R₄ are the same or different and each is hydrogen, an electronwithdrawing group, C₁-C₂₀ alkyl, C₁-C₂₀ alkyl substituted by an electronwithdrawing group, or R₃ and R₄ taken together form a carbocyclic ringor a heterocyclic ring, wherein the carbocyclic ring or heterocyclicring can be substituted by an electron withdrawing group, provided that(i) R₁, R₂, R₃, and R₄ are not all hydrogen; (ii) if R₁ and R₂ arehydrogen, then R₃ and R₄ are not both unsubstituted C₁-C₂₀ alkyl; and(iii) if R₁ and R₂ are hydrogen, and either of R₃ and R₄ is hydrogen,then the other of R₃ and R₄ is not polyethylenimine.

In certain embodiments, the repeat unit of A is divinylbenzene orstyrene. In certain embodiments, the repeat unit of B isN-vinylpyrrolidone or N-vinyl acetamide. In a preferred embodiment, thecopolymer is a poly(divinylbenzene-co-N-vinylpyrrolidone) copolymer.

In one embodiment, A and B form a porous particle. In anotherembodiment, A and B form a porous monolith.

The ion-exchange functional group is represented by X in formula Iabove. Preferably, the ion-exchange functional groups are present at aconcentration of about 0.01 to about 1.0, more preferably at aconcentration of about 0.2 to about 0.8, more preferably yet at aconcentration of about 0.4 to about 0.6, and still more preferably at aconcentration of about 0.5 milliequivalents per gram of porous material.

In certain embodiments, the ion-exchange functional moiety representedby X is an amine selected from the group consisting of an acyclicsecondary amine exclusive of polyethylenimine, a cyclic tertiary amine,a substituted acyclic amine, and a substituted cyclic amine. In suchembodiments, the ion-exchange functional moiety is formed by reaction ofa haloalkyl group with an appropriate starting amine to form the amineselected from the group consisting of an acyclic secondary amine, acyclic tertiary amine, a substituted acyclic amine, and a substitutedcyclic amine.

More particularly, the haloalkyl group, either introduced at theappropriate position on the phenyl ring after copolymerization (seeExample 2 below) or as a pre-existing substituent on the phenyl ring ofrepeat unit C (see Example 4 below), is reacted with the appropriatestarting amines (see Examples 3 and 5 below) in accordance withreactions and under conditions well-known to those of ordinary skill inthe art. The appropriate starting amine can be any of the primaryamines, cyclic secondary amines, substituted acyclic amines andsubstituted cyclic secondary amines described above.

In certain embodiments of the copolymer of formula I above, the electronwithdrawing group is selected from the group consisting of halogens,aromatic groups, e.g., pyridyl, hydroxy groups, unsaturated groups,ethers, thioethers, nitriles, nitro groups, esters, amides, carbamates,ureas, carbonates, sulfonamides, sulfones, and sulfoxides. In certainembodiments, the electron withdrawing group is a halogen, an ether, oran aromatic group.

In accordance with the invention, X can be any of the followingmoieties:

Preferred copolymers of Formula I include the following:

The porous materials of the invention can be prepared, e.g., byfunctionalizing, i.e., chemically altering, a copolymer having at leastone hydrophobic repeat unit and at least one hydrophilic repeat unit.The order of repeat units may be random, block, or combinations ofrandom and block.

The hydrophobic repeat unit may be derived from a variety of hydrophobicmonomer reagents possessing one or more polymerizable moieties, capableof undergoing polymerization, e.g., a free radical-mediatedpolymerization. Examples of hydrophobic monomers include but are notlimited to divinylbenzene, styrene, ethylvinylbenzene, andvinylbenzylchloride. Preferably, the hydrophobic monomer isdivinylbenzene.

The hydrophilic repeat unit may be derived from a variety of hydrophilicmonomer reagents possessing one or more polymerizable moieties, capableof undergoing polymerization, e.g., a free radical-mediatedpolymerization. Examples of hydrophilic monomers include but are notlimited to N-vinylpyrrolidone, N-vinylacetamide, N-vinylpyridine,methacrylate, methyl methacrylate, vinyl acetate, acrylamide ormethacrylamide. Preferably, the hydrophilic monomer isN-vinylpyrrolidone.

The copolymer can be prepared via a number of processes and mechanismsincluding, but not limited to, chain addition and step condensationprocesses, radical, anionic, cationic, ring-opening, group transfer,metathesis, and photochemical mechanisms. The copolymer can be preparedvia standard synthetic methods known to those skilled in the art, e.g.,as described in Example 1. Such a copolymer, e.g.,poly(divinylbenzene-co-N-vinylpyrrolidone), can be functionalized by theaddition of an ion-exchange functional group, e.g., the X group definedabove in formula I. In a preferred embodiment, X is

The novel materials of the invention, e.g., in the form of porousparticles or monoliths, can be used for solid phase extraction andchromatography. Thus, the invention also provides a porous material forsolid phase extraction or chromatography comprising at least oneion-exchange functional group, at least one hydrophilic component and atleast one hydrophobic component. The ion-exchange functional groupsenable the porous material to interact with basic and cationic solutes.The hydrophilic polar components enable the porous material to havepolar interactions and hydrogen bonding capabilities with solutes. Thehydrophobic components enable the porous material to have affinitytowards nonpolar solutes through hydrophobic interaction. Since theporous materials of this invention have a combination of variousinteraction forces towards solutes, they are very useful materials for,e.g., solid phase extraction, ion-exchange, and liquid chromatographyapplications. For example, these novel porous materials can be used tobind, recover and/or remove solutes from fluids.

The invention also provides a method for removing or isolating acomponent, e.g., a solute, from a mixture. A solution having a solute iscontacted with a porous material of the invention under conditions thatallow for sorption of the solute to the porous material.

The solute can be, e.g., any molecule having a hydrophobic, hydrophilic,or ionic interaction or a combination of two or three of theseinteractions. Preferably, the solute is an organic compound of polaritysuitable for adsorption onto the porous material. Such solutes include,e.g., drugs, pesticides, herbicides, toxins and environmentalpollutants, e.g., resulting from the combustion of fossil fuels or otherindustrial activity, such as metal-organic compounds comprising a heavymetal such mercury, lead or cadmium. The solutes can also be metabolitesor degradation products of the foregoing materials. Solutes alsoinclude, e.g., biomolecules, such as proteins, peptides, hormones,polynucleotides, vitamins, cofactors, metabolites, lipids andcarbohydrates.

The solution e.g., can comprise water, an aqueous solution, or a mixtureof water or an aqueous solution and a water-miscible polar organicsolvent, e.g., methanol, ethanol, N,N-dimethylformamide,dimethylsulfoxide or acetonitrile. In a preferred embodiment, thesolution is an acidic, basic or neutral aqueous, i.e., between about 1%and about 99% water by volume, solution. The solution comprising thesolute can, optionally, further contain one or more additional solutes.In one embodiment, the solution is an aqueous solution which includes acomplex variety of solutes. Solutions of this type include, e.g., blood,plasma, urine, cerebrospinal fluid, synovial fluid and other biologicalfluids, including, e.g., extracts of tissues, such as liver tissue,muscle tissue, brain tissue or heart tissue. Such extracts can be, e.g.,aqueous extracts or organic extracts which have been dried andsubsequently reconstituted in water or in a water/organic mixture.Solutions also include, e.g., ground water, surface water, drinkingwater or an aqueous or organic extract of an environmental sample, suchas a soil sample. Other examples of solutions include a food substance,such as a fruit or vegetable juice or milk or an aqueous oraqueous/organic extract of a food substance, such as fruit, vegetable,cereal or meat. Other solutions include, e.g., natural productsextractions from plants and broths.

The solution can be contacted with the porous material in any fashionwhich allows sorption of the solute to the porous material, such as abatch or chromatographic process. For example, the solution can beforced through a porous polymer column, disk or plug, or the solutioncan be stirred with the porous material, such as in a batch-stirredreactor. The solution can also be added to a porous material-containingwell of a microtiter plate. The porous material can take the form of amonolith or particle, e.g., beads or pellets. The solution is contactedwith the porous material for a time period sufficient for the solute ofinterest to substantially sorb onto the porous material. This period istypically the time necessary for the solute to equilibrate between theporous material surface and the solution. The sorption or partition ofthe solute onto the porous material can be partial or complete.

The invention also includes a method for analytically determining thelevel of solute in a solution. A solution having a solute is contactedwith a porous material under conditions so as to allow sorption of thesolute to the porous material. The material comprises at least oneion-exchange functional group, at least one hydrophilic polar componentand at least one hydrophobic component. The porous material having thesorbed solute is washed with a solvent under conditions so as to desorbthe solute from the porous material. The level of the desorbed solutepresent in the solvent after the washing is analytically determined.

The solution contacted with the porous material can comprise the soluteof interest in dilute form, e.g., at a concentration too low foraccurate quantitation. By sorbing the solute onto the porous materialand then, e.g., desorbing the solute with a substantially smaller volumeof a less polar solvent, a solution which includes the solute ofinterest can be prepared having a substantially higher concentration ofthe solute of interest than that of the original solution. The methodcan also result in solvent exchange, that is, the solute is removed froma first solvent and re-dissolved in a second solvent.

Solvents which are suitable for desorbing the solute from the porousmaterial can be, e.g., polar water-miscible organic solvents, such asalcohols, e.g., methanol, ethanol or isopropanol, acetonitrile, acetone,and tetrahydrofuran, or mixtures of water and these solvents. Thedesorbing solvent can also be, e.g., a nonpolar or moderately polarwater-immiscible solvent such as dichloromethane, diethylether,chloroform, or ethylacetate. Mixtures of these solvents are alsosuitable. Preferred solvents or solvent mixtures must be determined foreach individual case. A suitable solvent can be determined by one ofordinary skill in the art without undue experimentation, as is routinelydone in chromatographic methods development (see, e.g., McDonald andBouvier, eds., Solid Phase Extraction Applications Guide andBibliography, “A Resource for Sample Preparation Methods Development,”6th edition, Waters, Milford, Mass. (1995); Snyder and Kirkland,Introduction to Modern Liquid Chromatography, New York: J. Wiley andSons (1974)).

The level of the desorbed solvent present in the solvent can beanalytically determined by a variety of techniques known to thoseskilled in the art, e.g., high performance liquid chromatography, gaschromatography, gas chromatography/mass spectrometry, or immunoassay.

The invention also provides separation devices comprising the porousmaterials of the invention. Such devices include chromatographiccolumns, cartridges, thin layer chromatographic plates, filtrationmembranes, sample clean up devices, solid phase organic synthesissupports, and microtiter plates. In certain embodiments, more than onetype of functionalized porous material can be used in the separationdevices, e.g., columns, cartridges, and the like.

As noted above, the porous materials of the invention are especiallywell suited for solid phase extraction. Thus, the invention alsoincludes a solid phase extraction cartridge comprising a porous materialof the invention packed inside an open-ended container. In oneembodiment, the porous material is packed as particles within theopen-ended container to form a solid phase extraction cartridge.

The container can be, e.g., a cylindrical container or column which isopen at both ends so that the solution can enter the container throughone end, contact the porous material within the container, and exit thecontainer through the other end. In the form of porous particles, theporous material can be packed within the container as small particles,such as beads having a diameter between about 3 μm and about 500 μm,preferably between about 20 μm and about 200 μm. In certain embodiments,the porous particles can be packed in the container enmeshed in a porousmembrane.

The container can be formed of any material which is compatible, withinthe time frame of the solid phase extraction process, with the solutionsand solvents to be used in the procedure. Such materials include glassand various plastics, such as high density polyethylene andpolypropylene. In one embodiment, the container is cylindrical throughmost of its length and has a narrow tip at one end. One example of sucha container is a syringe barrel. The amount of porous material withinthe container is limited by the container volume and can range fromabout 0.001 g to about 50 kg, and preferably is between about 0.025 gand about 1 g. The amount of porous material suitable for a givenextraction depends upon the amount of solute to be sorbed, the availablesurface area of the porous material and the strength of the interactionbetween the solute and the porous material. This amount can be readilydetermined by one of ordinary skill in the art. The cartridge can be asingle use cartridge, which is used for the treatment of a single sampleand then discarded, or it can be used to treat multiple samples.

EXAMPLES

The present invention may be further illustrated by the followingnon-limiting examples. All reagents were used as received unlessotherwise noted. Those skilled in the art will recognize thatequivalents of the following supplies and suppliers exist, and as suchthe suppliers listed below are not to be construed as limiting.

Example 1

To a 3000 mL flask was added a solution of 5.0 ghydroxypropylmethylcellulose (Methocel E15, Dow Chemical Co., Midland,Mich.) in 1000 mL water. To this was added a solution of 175 gdivinylbenzene (DVB HP-80, Dow), 102 g N-vinylpyrrolidone (InternationalSpecialty Products, Wayne, N.J.), and 185 g azobisisobutyronitrile (VAZO64, Dupont Chemical Co., Wilmington, Del.) in 242 g toluene (J. T.Baker, Phillipsburgh, N.J.). The 80% purity divinylbenzene above may besubstituted with other hydrophobic monomers such as styrene orethylvinylbenzene, or lower purity grades of divinylbenzene, but 80%purity divinylbenzene is preferred. The divinylbenzene is stripped witha sodium hydroxide solution prior to use in the normal way. TheN-vinylpyrrolidone above may be substituted with other hydrophilicmonomers such as N-vinylacetamide, N-vinylpyridine, methacrylate, methylmethacrylate, vinyl acetate, acrylamide, methacrylamide, butN-vinylpyrrolidone is most preferred.

The resulting biphasic mixture was stirred for 30 minutes at roomtemperature using sufficient agitation to form oil droplets of thedesired micron size. The resulting suspension was then heated undermoderate agitation at 70° C. and maintained at this temperature for 20hours. The suspension was cooled to room temperature, filtered, andwashed with methanol. The filter cake was then dried in vacuo for 16hours at 80° C. The composition of the product polymer was determined bycombustion analysis (CE-440 Elemental Analyzer; Exeter Analytical Inc.,North Chelmsford, Mass., or equivalent). Elemental analysis N 2.24%;mole percent N-vinylpyrrolidone: 20%. A series ofpoly(divinylbenzene-co-N-vinylpyrrolidone) copolymers comprising about13, 14, 16, and 22 mole % N-vinylpyrrolidone was also prepared by thismethod varying the starting ratio of the divinylbenzene andN-vinylpyrrolidone monomers.

Example 2

Poly(divinylbenzene-co-N-vinylpyrrolidone), OASIS® HLB, obtained fromWaters Corp., Milford, Mass., was derivatized with hydrochloric acid (12Molar, 36.5-38%, A.C.S. reagent, J. T. Baker, 9535-03, Phillipsburgh,N.J.) and paraformaldehyde (95%, Aldrich Chemical, 15, 812-7, Milwaukee,Wis.). A three-necked, round-bottom flask was fitted with a thermometer,agitator, condenser and reactor temperature control system. Hydrochloricacid was introduced into the flask. In some cases, water was added tothe flask prior to hydrochloric acid addition in order to dilute theacid concentration to below 12 M. Then, the agitation and thetemperature control were started. The agitator was a ground-glass shaftfitted through the proper Teflon bearing into the center opening atopthe flask. The Teflon paddle was single-bladed. The agitation rate wasadjusted to ensure adequate mixing. Thepoly(divinylbenzene-co-N-vinylpyrrolidone), OASIS® HLB, was charged.Next, the paraformaldehyde was charged. The reaction mixture was stirredfor a certain period of time at constant temperature. The reactionmixture was cooled, and the acid solution was filtered. Thechloromethylated poly(divinylbenzene-co-N-vinylpyrrolidone) copolymerwas collected and washed with water until the pH of the slurry was ≧5.0.In the case of Examples 2s and 2u, the copolymer was washed with wateruntil the pH was ≧3, and then a requisite amount of concentratedammonium hydroxide was added to bring the pH between 8 and 9. Thematerials were then water washed until the pH was ˜7. The filter cake ofchloromethylated poly(divinylbenzene-co-N-vinylpyrrolidone) copolymerwas then washed twice with methanol (HPLC grade, J. T. Baker, 9535-03,Phillipsburgh, N.J.) and dried in vacuo for 15 hours at 80° C. In thecase of Examples 2t and 2u, the copolymer was dried directly from thewater wet state with no methanol wash. The level of chloromethylationwas determined by chlorine elemental analysis (Atlantic Microlab Inc.,Norcross, Ga.). Reagent amounts, reaction conditions, and the resultantloading of chloromethyl groups (CH₂Cl) are listed in Table 1.

TABLE 1 Reaction Oasis ® Chloromethyl Temperature Reaction HCl HLB HClParaformaldehyde Loading Product (° C.) Time (h) Molarity (g) (g) (g)(meq/g) 2a 50 1 11.1 30 450 17 0.61 2b 60 16 7.5 25 385 4.5 0.72 2c 40 212.0 16 225 17 0.73 2d 50 2 11.1 30 450 17 0.74 2e 50 2 12.0 16 225 150.83 2f 50 6 11.1 30 450 17 0.89 2g 50 16 11.1 30 450 17 1.00 2h 60 169.0 25 385 14.5 1.01 2i 70 2 11.1 30 450 17 1.03 2j 60 5 12.0 16 250 81.14 2k 60 16 10.5 25 385 14.5 1.15 2l 70 16 1.1 30 450 17 1.23 2m 70 611.1 30 450 17 1.24 2n 60 25 12.0 16 250 8 1.35 2o 65 21 12.0 5 150 81.38 2p 70 25 12.0 61 926 51 1.43 2q 65 24 12.0 500 9000 290 0.93 2r 6024 12.0 100 1500 58 1.09 2s Same batch as 2r (10 g sample), but with0.95 ammonium hydroxide addition. 2t 65 24 12.0 40 600 23.2 1.20 2u Samebatch as 2t (20 g sample) but with 1.15 ammonium hydroxide addition

Example 3

Chloromethylated poly(divinylbenzene-co-N-vinylpyrrolidone) porousmaterials, prepared as described in Example 2, were reacted with thefollowing amines (all purchased from Aldrich Chemical, Milwaukee, Wis.):Piperidine (PP), piperazine (PZ), N-methylpiperazine (MPZ),N-methylbenzylamine (MBZ) and morpholine (M). A general procedure isprovided below. Reagent amounts, reaction conditions, and the resultantloading of amine groups are listed in Table 2.

A 250 mL, three-necked, round-bottom flask was fitted with athermometer, agitator, condenser and reactor temperature control system.The amine was introduced into the flask, and the agitation and thetemperature control were started. In the case of Examples 3b and 3g, thereaction suspension also included a charge of water. The agitator was aground-glass shaft fitted through the proper Teflon bearing into thecenter opening atop the flask. The Teflon paddle was single-bladed. Thechloromethylated poly(divinylbenzene-co-N-vinylpyrrolidone) was charged,and the agitation rate was adjusted to ensure adequate mixing. Thereaction mixture was stirred for a certain period of time at constanttemperature. The reaction mixture was cooled, and the amine wasfiltered. The aminated poly(divinylbenzene-co-N-vinylpyrrolidone)copolymer was collected and washed with water until the pH of the slurrywas ≧7.0. The filter cake of aminatedpoly(divinylbenzene-co-N-vinylpyrrolidone) copolymer was then washedtwice with methanol (HPLC grade, J. T. Baker, 9535-03, Phillipsburgh,N.J.) and dried in vacuo for 15 hours at 80° C. The loading of amine wasdetermined by fully converting the amine to its hydrochloride salt withdilute hydrochloric acid, displace the chloride of the salt by exposingthe material to dilute nitric acid, and then titrating the displacedchloride in solution with AgNO₃ (Metrohm 716 DMS Titrino autotitratorwith silver electrode, Metrohm, Hersau, Switzerland, or equivalent).

TABLE 2 Chloro- Chloro- Amine Reaction methyl methyl Amine GroupTemperature Time product load Amine Amount Loading Product (° C.) (h)(g) (meq/g) Type (g or mL) (meq/g) 3a 105 18 73 1.10 PP 730 g 0.37 3b100 18 15 0.69 PZ 12.9 g in 0.36 150 mL water 3c 110 18 15 0.69 MPZ 1500.43 3d 110 18 15 0.69 M 150 0.16 3e 110 18 20 1.24 MBZ 200 0.2 3f 11018 20 0.93 M 135 0.18 3g 100 18 20 0.93 M 17.5 mL in 0.17 100 mL water

Example 4

This example illustrates the preparation ofpoly(divinylbenzene-co-N-vinylpyrrolidone) andpoly(divinylbenzene-co-N-vinylpyrrolidone-co-vinylbenzylchloride)monolithic copolymers. A general procedure is provided below. Reagentamounts, reaction conditions, and characterization data are listed inTable 3.

To a 20 mL glass vial was added N-vinylpyrrolidone (NVP, AldrichChemical, Milwaukee, Wis.), divinylbenzene (DVB HP-80, Dow),cyclohexanol (CH, Aldrich Chemical, Milwaukee, Wis.), dodecanol (DD,Aldrich Chemical, Milwaukee, Wis.) and azobisisobutyronitrile (VAZO 64,Dupont Chemical Co., Wilmington, Del.). In some cases Vinylbenzylchloride was also added (VBC, Fluka, Milwaukee, Wis.). These mixtureswere mixed and purged with nitrogen for 5 minutes before 5 mL aliquotswere transferred to individual 10 mL glass vials. Each of these vialswas placed in an oven at 75° C. for 24 hours. Following removal from thevials, each monolith was placed in refluxing methanol for 32 hours andthen dried for 24 hours at 75° C. and an additional 24 hours at 85° C.under vacuum. The level of chloromethylation was determined by chlorineelemental analysis (Atlantic Microlab Inc., Norcross, Ga.). Reagentamounts, % C, porosity data, and the resultant loading of chloromethylgroups (CH₂Cl) are listed in Table 3.

The % C was determined as in Example 1. The resultant loading ofchloromethyl groups (CH₂Cl) was determined as in Example 2. The specificsurface areas (SSA), specific pore volumes (SPV) and the average porediameters (APD) of these materials were measured using the multi-pointN₂ sorption method (Micromeritics ASAP 2400; Micromeritics InstrumentsInc., Norcross, Ga., or equivalent). The specific surface area wascalculated using the BET method, the specific pore volume was the singlepoint value determined for P/P₀>0.98, and the average pore diameter wascalculated from the desorption leg of the isotherm using the BJH method.The macropore pore volume (MPV) of the resultant materials was measuredby Mercury Porosimetry (Micromeritics AutoPore II 9220 or AutoPore IVMicromeritics, Norcross, Ga., or equivalent).

TABLE 3 NVP DVB CH DD AIBN VBC SSA TPV APD Cl MPV Product (g) (g) (g)(g) (g) (g) % C (m²/g) (cm³/g) (Å) (meq/g) (mL/g) 4a 2.2 3.9 10.8 1.20.08 0 81.9 394 0.72 120 0 0.54 4b 2.2 3.3 10.8 1.2 0.08 0.76 87.3 6571.31 117 0.92 1.42 4c 2.0 3.5 10.8 1.2 0.08 0.76 87.1 653 1.25 112 0.891.48

Example 5

Monoliths of the type 4b were placed in 100 mL round bottom flasksequipped with reflux condensers, containing 50 mL of eithermethylpiperazine (MPZ), N-methylbenzylamine (MBZ) (Aldrich Chemical,Milwaukee, Wis.). The flasks were heated for 16 hours, at which point,they were cooled and the monoliths removed. The monoliths were thenplaced in refluxing methanol for 24 hours (replaced with fresh methanolafter 12 hours), before being dried for 24 hours at 85° C. under vacuum.Amine type, reaction temperature, and the resultant loading of aminegroups are listed in Table 4. The % C and % N were determined as inExample 1. The loading of amine was determined as described in Example3.

TABLE 4 Temperature Amine Load Product Amine (° C.) % C % N (meq/g) 5aMPZ 110 86.6 2.75 0.36 5b MBZ 140 89.5 1.74 0.14

Example 6

Products of Example 3b and 3f were placed in 2.1×20 mm chromatographiccolumns were using a slurry packing technique. The packed columns weresubsequently employed in an modular valve switching system comprising a2777 Sample Manager, a 1525μ Binary HPLC pump, a 2-Position, 6-PortSolvent Selector Valve (two total), a 515 HPLC pump, (two total), aQuattro Ultima Pt detector, and MassLynx 4.0 software (all from WatersCorporation, Milford, Mass., or equivalent). An 80 μL injection ofdipyrone (Sigma-Aldrich, Milwaukee, Wis.) in a water solution (10 ng/mL)was loaded onto the column in a water mobile phase containing 3% formicacid for 1 minute at 4 mL/min. The column was then washed with amethanol solution containing 3% formic acid for 1 minute at 4 mL/min.The dipyrone was then eluted from the column with a 95:5 (v/v)methanol:3% NH₄OH water mobile phase at 0.4 mL/min. FIGS. 1 and 2 showthe total ion chromatograms (TIC) for the elution of dipyrone using theproducts of Example 3b and 3f respectively.

Example 7

Products of Example 3b and 3f were placed into 1 cc cartridges (30mg/cartridge) using a dry packing technique. Each cartridge wasconditioned with 1000 μL methanol and then conditioned with 1000 μLwater. A 1000 μL sample was loaded which consisted of isotonic salinespiked with the following analytes: 2-naphthalenesulfonic acid (2.5 μg),amitriptyline (5 μg), ketoprofen (15 μg), salicylic acid (7.5 μg),secobarbital (12.5), 4-propylbenzoic acid (15 μg). Each loaded cartridgewas washed with 1000 μL 25 mM sodium acetate, pH=4 (designated Fraction1), and then washed with 1000 μL of methanol (designated Fraction 2).Next each cartridge was eluted with 1000 μL of 2% ammonium hydroxide in20:80 (v:v) methanol-acetonitrile (designated Fraction 3) and theneluted again with 500 μL of 2% ammonium hydroxide in 20:80 (v:v)methanol-acetonitrile (designated Fraction 4). All fractions after theequilibration were collected, and 500 μL of 0.1 mg/mL butyl paraben inacetonitrile was added as an internal standard. Fraction 1 was thendiluted with 1000 μL of 2% formic acid in 20:80 (v:v)methanol-acetonitrile. Fractions 2 and 3 were then diluted with 1000 μLof saline. Fraction 4 was diluted with 500 μL of saline. All fractionswere diluted with 100 μL of concentrated phosphoric acid prior toinjection. All analytes were from Sigma-Aldrich (Milwaukee, Wis.), allreagents were from J. T. Baker (Phillipsburgh, N.J.).

Each fraction was measured for sample recovery using the following HPLCequipment and method (all from Waters Corporation, Milford, Mass. orequivalent): Waters 600 HPLC pump; Waters 717 autosampler; Waters 486 UVdetector; 3.5 μm SymmetryShield™ RP₈ column, 4.6×75 mm; Mobile phase68:32 (v:v) 20 mM K₂HPO₄, pH 2.7—acetonitrile; Flow rate was 2.0 mL/min;Temperature 35° C. Detection UV at 214 nm. Injection volume 15 μL.Percent recoveries and the corresponding % RSD are listed in Table 5 forthe average of two runs.

TABLE 5 Analyte % Analyte Recovery Fraction Fraction Fraction Product 12 3 Fraction 4 % RSD 3b 2-naphthalenesulfonic 0.0 0.0 97.6 0.0 0.05 acidamitriptyline 0.0 93.3 0.0 0.0 0.53 ketoprofen 0.0 0.0 96.3 0.0 0.18salicylic acid 0.0 0.0 96.7 0.0 0.25 secobarbital 0.0 94.0 0.0 0.0 0.08propylbenzoic acid 0.0 0.0 95.2 0.0 0.01 3f 2-naphthalenesulfonic 0.00.0 92.5 1.1 2.33 acid amitriptyline 0.0 93.5 0.0 0.0 1.86 ketoprofen0.0 91.8 2.8 0.0 1.45 salicylic acid 0.0 4.3 88.4 0.0 0.97 secobarbital0.0 94.7 0.0 0.0 1.27 propylbenzoic acid 0.0 96.7 0.0 0.0 1.04

INCORPORATION BY REFERENCE

The entire contents of all patents, published patent applications andother references cited herein are hereby expressly incorporated hereinin their entireties by reference.

EQUIVALENTS

Those skilled in the art will recognize, or be able to ascertain usingno more than routine experimentation, numerous equivalents to thespecific procedures described herein. Such equivalents were consideredto be within the scope of this invention and are covered by thefollowing claims. The contents of all references, issued patents, andpublished patent applications cited throughout this application arehereby incorporated by reference.

1. A method for removing or isolating a component from a mixturecomprising: contacting the mixture with a chromatographic materialcomprising a porous material comprising a copolymer of at least onehydrophobic monomer and at least one hydrophilic monomer, wherein saidcopolymer further comprises at least one ion-exchange functional moietycomprising a piperazinyl moiety, to thereby remove or isolate thecomponent from the mixture; wherein said hydrophilic monomer isN-vinylpyrrolidone.
 2. A method for determining the level of a componentin a mixture, comprising: contacting the mixture with a chromatographicmaterial comprising a porous material comprising a copolymer of at leastone hydrophobic monomer and at least one hydrophilic monomer, whereinsaid copolymer further comprises at least one ion-exchange functionalmoiety comprising a piperazinyl moiety under conditions that allow forsorption of the component onto the porous material; washing thechromatographic material having the sorbed component with a solventunder conditions so as to desorb the component from the porousmaterials; and determining the level of the desorbed component; whereinsaid hydrophilic monomer is N-vinylpyrrolidone.